Telegraph and telephone wire



(No Model.)

G. GRAY;

TELEGRAPH AND TELEPHONE WIEE.

No. 290,769. I Patented Dec. 25, 1883.

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WE ZW ATTORNEYS UNITED STATES PATENT rricn,

GORHAMI GRAY, OF BOSTON, MASSACHUSETTS.

TELEGRAPH AND TELEPHONE WIRE.

To all whom it may concern.-

Be it known that I, GORHAM GRAY, of Boston, in the county of Suffolk andState of Massachusetts, have invented certain new and use fulImprovements in Telegraph and Telephone fires; and I do herebydeclarethat the followingis a full, clear, and exact description of theinvention, which will enable others skilled in the art to which itappertains to make and use the same, reference being had totheaccompanying drawings, which form a part of this specification.

My invention has relation to wires for telegraph and telephone lines;and it consists in an anti-inductive wire, as hereinafter more fullydescribed and claimed.

In telephone-wires as now ordinarily constructed, great difficulty isexperienced, especially on long lines, in carrying on plain andintelligible conversation between two points connectedby the wire, onaccount of induction from other wires in proximity to the telephonewire;and my improvement consists in an insulated wire of the form describedand claimed, whereby I have found, by practical experiment over longlines and amidst a system of other wires, that the induction is greatlylessened, and the conversation carried on between the two points at theopposite ends of the wire EOIFICATION forming part of Letters Patent No.290,769, dated December 25, 1883,

Application filed January 3, 1883.

(No model.)

made very much plainerand more intelligible, owing to the anti-inductiveproperties of my improved wire.

In the accompanying drawings, Figure 1 represents a perspective view ofa piece of my improved wire, and Fig. 2 is a cross-section on anenlarged scale of the same, like letters of reference indicatingcorresponding parts in both the figures.

By reference to these figures it will be seen that I form my improvedanti-inductive wire with a series of spiral grooves, B, formed byindenting the metal of the wire body A. The special machinerywherebythese spiral grooves are formed forms the subject of anotherapplication for Letters Patent.

I claim as my invention and desire to secure by Letters Patent of theUnited States An anti-inductive device for telegraph and telephonelines, consisting ofa spirallygrooved wire, substantially as set forth.

In testimony that I claim the foregoing as my own I have hereuntoaffixed my signature in presence of two witnesses.

GORHAM GRAY.

Vitnesses:

ALVAH L. Swnrr, J. F. REILY.

